If the Outlook module in Avast is set up to scan only email attachments, do emails without attachments also get “signatures” embedded; i.e., the signatures from the “Insert signatures into clean messages” option ???
If you scan only attachments, as far I know, the messages won’t be added. But it will be good if Vojtech (from Alwil team) confirm this.
How did you get to that option window?
My window for email just shows this-
Select Outlook/Exchange plugin and not Internet Mail provider.
Ahhh right got it now…thanks 
One thing I have noticed since having Avast, the replies to any questions on the forums is super fast 
You’ve discovered the avast forum speed 8)
lol yeah, I must say that I’m very impressed so far, for a product that’s free!!!
I guess that the answer is “yes.” It seems odd that unscanned emails get labeled as “clean”-- that is, if Avast is set up to only scan email attachments, emails without attachment will also get tagged with a message that it’s clean, if the tagging clean message option is checked.
This seems like a bug to get fixed.
Are you talking about the situation when you disable scanning of message bodies?
Yes. If scanning of message bodies is disabled, emails without attachments can still get labeled “clean” (the insert message into clean messages option), even though those emails are not scanned.
If that is the case then I see even less reason to insert clean notes into received emails.
Personally I don’t trust any received email received signed or otherwise, whilst the inbound emails that are scanned by avast if there was a problem then all hell breaks loose and you know there is a problem. I certainly take no notice of emails signed by other AVs on sending.
So if you are only intending to scan emails with attachments then personally I wouldn’t bother with the clean note insertion.